Bankroll management can't replace strategy even though it is a very important tool in every gambler's toolbox. The reality is that if you have an excellent bankroll management but with a terrible strategy with little to no win rate, then the bankroll being "managed" will eventually diminish untill all of it is lost.

I think of it like this:

Good bankroll management + good strategy = more Ws than Ls.
Bad bankroll management + good strat = 50/50 because one loss can wipe out multiple wins.

Good bankroll management +bad strategy + more Ls than Ws simply because it doesn't matter what you're managing because losses will keep piling up.